when i press the start button on my pc, only the tower is activated without opening the screen or the keyboard. I turn off my pc and when i move the cables a bit, the pc works normally. i try other hdmi cable for my screen but nothing happened. that happened often but not everyday. i tried take off all cables but cables looks good without damage. i dont use any adapter. my pc never dropped . i don't know if have problem with any piece. what could be wrong? Also i can send here a video when start my pc .